1. Field of the Invention
This invention relates generally to rotating electric machines, and more specifically to a system for mounting brushes on an automotive vehicle alternator which comprises an assembly of a bearing sleeve, the brush holder, and a cap.
2. Background Information
A known automotive vehicle electrical system comprises a D.C. storage battery that is kept charged by an alternator that is powered by the vehicle's engine. Like similar rotating electric machines, a known automotive vehicle alternator contains electrically conductive brushes that are disposed in a brush holder mounted on a non-rotating portion of the electric machine and are spring-biased against conductive rings on a rotating portion of the machine for conveying electric current between rotating and non-rotating elements.
A known technique for mounting a brush holder on an alternator comprises joining the brush holder and a second piece together, such as by molding the second piece onto the brush holder for example, and then attaching the assembled pieces to the alternator housing, for example by fastening the second piece to the rear of the alternator housing by threaded fasteners. An example of this technique is represented by a Ford model 3G brush holder assembly.
Another known technique comprises integrating the brush holder with a rear bearing sleeve of the alternator. An example of this technique appears in U.S. Pat. No. 5,296,772.
It is believed to important for a brush holder to be rigidly mounted on an alternator in order to avoid potentially detrimental effects from repeated vibration to which the alternator is subjected during use on an automotive vehicle engine.
U.S. Pat. Nos. 3,233,130; 3,963,949; 4,680,495; 4,959,576; and 5,345,132; are believed representative of the state of the art. They disclose various forms of brush holder mountings.